Numerous flotation aids for use in swimming are available. One commonly used flotation device is a pull buoy, which can be used to immobilize and float a swimmer's legs in order to allow the swimmer to focus on his/her upper body motions. Existing pull buoy solutions require varying degrees of inconveniences while swimming. The predominant design is a singular figure eight form that the swimmer places between his/her thighs. This requires the swimmer to squeeze his/her thighs tightly to keep the buoy in place. The buoy requires frequent placement adjustments while swimming and is especially difficult to keep in place when kicking off a wall of a pool to change direction. Other pull buoys involve an ankle cuff with openings on the outside of each ankle cylinder which allows the swimmer to insert or remove his/her ankles from the buoy.
Another commonly used flotation device is a kickboard, which can be used to allow the swimmer to focus on his/her lower body motions. The predominant kickboard designs involve a floating board or foam shape which the swimmer holds at surface level. This design requires the swimmer to assume an upright position with arms at water surface level and upper body and head above water. This position differs from a more hydrodynamic form when engaging in a crawl stroke where the head is facing underwater and hands target a position that is many inches below water surface at the farthest reach point.
In training sessions, swimmers will often do intervals where they switch between using a pull buoy, a kickboard, and other training devices. The swimmers often do not have much time to make the change before starting their next interval.